Process for electrolytically refining copper.



GEORGE D. VAN ARSDALE, OF EAST ORANGE, NEW JERSEY.

PROCESS FOR ELECTROLYTICALLY REFINING- COPPER.

No Drawing.

Specification of Lettersv Patent.

Application filed October 2, 1908. Serial No. 455,826.

Patented Aug. 5, 1913.

To all whom it may concern .1

Be it known that I, GEORGE D. VAN .Ans- DALE, a citizen of the United States of America, and a resident of East Orange,

county of Essex, and State of New Jersey,

have invented a certain new and Improved Process for Electrolytically Refining Oopper, of which the following is aspecification.

In 'the electrolytic refining of copper, as practised at the present day, the electrolyte employed is usually an acid solution of copper sulfate in which the copper present is in the cupric state. The employment of a cuprous compound in this connection, such as would fulfil the requirements of an electrolytic process, would be much more 'economical because a very much less power,' theoretically exactly one-half of the amount needed when cupric compounds are employed,is necessary when the copper is contained in a cuprous state. Many cuprous compounds however, are not soluble or are butslightly soluble and hence are not available. Furthermore, a number of soluble cuprous compounds are readily oxidizable and hence though cuprous when first employed would quickly pass to the cupric form. And again, certain cuprous compounds which might otherwise be available for this purpose, are useless on account of their action on certain constituents of the copper to be purified. I have found, however,'by experiment, that solutions of certain cuprous compounds form suitable electrolytes for electrolytically refining copper,

and when thus employed result in the. depo sition of substantially double the amount of metal in 'a given time, and with a given expenditure of power, which would be deposited in an apparatus employing electrolytes comprising solutions of cupric .salts. For example: There are several sulfites of copper and a number of double salts of the same which when in solution form suitable electrolytes. A solution of cupric sulfate may be made strongly ammoniacal and then impregnated with sulfur dioxid gas until all the copper is reduced to the'cuprous state. in the form of the double salt, ammonium cuprous sulfite, which will be kept in solu tion by other salts present. As another ex- The copper will then be probably ample,a readily soluble sulfite, such as sodium or ammonium sulfite, may be added in excess to asolution of a cupric salt; or

any cuprous sulfite, already existing as such,

may be dissolved by the addition of certain salts, such as'sodium or ammonium or other readily solubl sulfites; or such re- .ducing agents as phdsphorous acid or p h 9 s;

phites'may be used in a similar manner.

In'carrying out the process of purifying and refining the copper, I employ the copper to be treated as the anode in an electrolytic apparatus containing. the above defined electrolyte, and provide a suitable cathode for receiving the deposit. I then pass a current of electricity through the bath whereby copper is dissolved from the anode, passes through the electrolyte and 'is deposited upon the cathode in a refined and pure condition. The impurities are received or retained in the electrolyte and are then in a form convenient for further treatment, but in the meantime the solution remains ofuniform strength so far as copper is concerned,-because substantially'no more copper will be deposited upon the cathode than is dissolved from the anode.

Other salts or substances may be added to the electrolytic solution for specific purposes, as may be desired, such .as for increasing the conductivity thereof, or for decreasing the tendency to polarization, and details as to strength of solution, temperature, etc., may be varied to suit varying conditions.

The purification of the solution from accumulated impurities, may be carried out in any deslred manner, 'as this part of the process forms no part of my present inven-- tion. What I claimis:

1. The herein described! process of refining metallic copper which consists in dissolving the same electrolytically from a metallic anode thereof immersed in an electrolyte containing a soluble cuprous sulfite, and depositing the' dissolved copper upon a cathode also immersed within the said electrolyte.

2. The herein described process of refining metallic copper. which consists in dissolving the same electrolytically from a me- .t allic anode thereof immersed in an electrolyte containing ammonium ouprous sulthe cuprous state, the electrolyte alsoconfite, and depositing the dissolved copper taining a soluble sulfite. upon a cathode also immersed Within the GEORGE D. VAN ARSDALE. said electrolyte.

3. The herein described process Which con Witnesses: sists in separating copper by electrolysis D. HOWARD HAYWOOD, from an electrolyte containing copper in LYMAN S. ANDREWS, Jr. 

